This app is a client that uploads one image file to a server running on
i5.nyu.edu.
The server places the image in the
images
subdirectory of the server’s current directory,
which is
/home1/m/mm64/INFO1-CE9236/src/putimages
subdirectory by pointing your browser at
http://i5.nyu.edu/~mm64/INFO1-CE9236/src/put/images/.
I followed the example Simple URL Connections. Also see Estimating upload progress.
This source code is only the client.
You also need the server
server.py.
The client and server have to agree on the TCP/IP port number (3000).
To keep things simple, I put everything into class
View.
In real life,
the networking code would be in the application delegate
or in the view controller.
main.mPutAppDelegateView
Move or copy the image file
spj224.png
into the root folder of the project,
and add it to the project.
A TCP/IP server running on
i5.nyu.edu
must be bound to a port in the range
3000 to 3199 inclusive,
a policy set by our superuser.
The TCP/IP port numbers currently in use are the numbers after the
last (or only) dot in column 1:
netstat -an -f inet -P tcp
TCP: IPv4
Local Address Remote Address Swind Send-Q Rwind Recv-Q State
-------------------- -------------------- ----- ------ ----- ------ -----------
128.122.109.53.22 69.204.232.159.51486 524280 0 66608 0 ESTABLISHED
128.122.109.53.80 172.26.25.119.59544 524280 0 65664 0 FIN_WAIT_2
128.122.109.53.80 172.26.25.119.59546 524280 0 65664 0 FIN_WAIT_2
128.122.109.53.80 172.26.25.119.59547 524200 0 65664 0 FIN_WAIT_2
*.111 *.* 0 0 65536 0 LISTEN
*.* *.* 0 0 65536 0 IDLE
*.22 *.* 0 0 65536 0 LISTEN
*.7100 *.* 0 0 65536 0 LISTEN
*.6481 *.* 0 0 65536 0 LISTEN
*.80 *.* 0 0 65536 0 LISTEN
*.3306 *.* 0 0 65536 0 LISTEN
128.122.109.53.22 192.168.66.90.49281 524280 0 66608 0 ESTABLISHED
128.122.109.53.22 192.168.66.90.49285 524280 0 66608 0 ESTABLISHED
*.25 *.* 0 0 65536 0 LISTEN
The following shellscript is written in the language of the Korn Shell
(ksh).
It runs on
i5.nyu.edu.
#!/bin/ksh
#Output the TCP/IP port numbners currently in use.
netstat -an -f inet -P tcp |
awk 'NR > 4 {print $1}' | #Output the first field.
awk -F. '{print $NF}' | #Output the last field of the first field.
grep '^[0-9][0-9]*$' | #Discard any lines that are not all digits.
sort -nu #Increasing numerical order, discard duplicates.
exit 0
22 25 80 111 3306 6481 7100
You can also run
netstat
with the same command line arguments in the Terminal window on a Mac.
Here’s its
Mac manual page.
The server
server.py
is written in the language Python and runs on
i5.nyu.edu.
The server must be launched before the client tries to upload the image.
Launch it “in the background” with an ampersand
to let the shell prompt reappear immediately,
and with
nohup
so that the server keeps running even after we log out from
i5.nyu.edu.
cd /home1/m/mm64/public_html/INFO1-CE9236/src/put pwd nohup server.py & netstat -an -f inet -P tcp
The server produces the following output:
gImageDirPath == "./images" Server is running on i5.nyu.edu. Server has accepted a client. fileLength == 221607 filePath == "./images/spj224.png" ND-IMAC-13.NDLAB.ITS.NYU.EDU - - [17/Nov/2010 12:15:33] "PUT /spj224.png HTTP/1.1" 201 -
The server refuses to overwrite an existing file with the same name as the file being uploaded. It gives the message
ND-IMAC-13.NDLAB.ITS.NYU.EDU - - [17/Nov/2010 12:22:52] code 500, message Internal Server Error
Each line ends with the two characters
\r\n.
The last line consists of only the two characters
\r\n.
After that comes the bytes of the png file.
PUT /spj224.png HTTP/1.1 Host: i5.nyu.edu:3000 User-Agent: Put/1.0 CFNetwork/485.2 Darwin/10.4.0 Content-Type: image/png Content-Length: 221607 Accept: */* Accept-Language: en-us Accept-Encoding: gzip, deflate Connection: keep-alive